The value of ' $a$ ' for which one root of the quadratic equation $\left(a^2-5 a+3\right) x^3+(3 a-1) x+2=0$…
The value of ' $a$ ' for which one root of the quadratic equation $\left(a^2-5 a+3\right) x^3+(3 a-1) x+2=0$ is twice as large as the other is
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$-\frac{1}{3}$
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$\frac{2}{3}$
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$-\frac{2}{3}$
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$\frac{1}{3}$
Solution
$3 \alpha=\frac{1-3 a}{a^2-5 a+3} \& 2 \alpha^2=\frac{2}{a^2-5 a+3}$
$2\left[\frac{1}{9} \frac{(1-3 a)^2}{\left(a^2-5 a+3\right)^2}\right]=\frac{2}{a^2-5 a+3}$
$\frac{(1-3 a)^2}{\left(a^2-5 a+3\right)}=9$ or $9 a^2-6 a+1$
$=9 a^2-45 a+27$ or $39 a=26$ or $a=\frac{2}{3}$
Asked in: JEE Main 2003
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